Fast accumulator ticking but its not the sphere....?

vince · Unread post by **vince** » 21 Jun 2009, 08:34

Hi guys, at the moment my accumulator is clicking every 8 seconds when idling on level ground with just the handbrake on. The LHM level is spot on and i cant see any leaks anywhere....? I know its not the sphere as this was pressure tested at Jims last weekend and its still as new on 62bar

What else could it be?

It has always been fine at 30 seconds until it was discovered that the Hydractive wasnt working on mine and that was fixed with a diode kit and the rear connection cleaned and replugged in. Since then it has decided that 8 seconds is a good interval for clicking

Also the rear of the car sinks on its own when parked on my drive (only sometimes) where as before it didnt, and the rear jumps up a bit when its started like that, but then sometimes it comes up smooth?

Thoughts people?

Unread post by **CitroJim** » 21 Jun 2009, 08:55

Hi Vince

I have been wondering why your rear electrovalve was disconected and now perhaps the secret is beginning to come out

I suspect that this low tick rate may have been pre-existing and was bodged by disabling the rear electrovalve.

You can easily check this by disabling the hydractive again by removing F8 (20A yellow) in the engine bay fuse box. As you look it will be the middle fuse in the left-hand row. Remove it with ignition off and then strat up. If your tick rate goes up to the normal 30s, you have a clue.

I'm suspecting that the rear electrovalve is leaky internally and has an excessive leakage return. You can check this by getting the rear up on ramps and disconnecting the black leakage return pipe from the top of the electrovalve and substituting a temporary leakage return pipe into a jamjar. You can then see how much leaks out in soft mode. It should only be a dribble.

I've just had to replace my rear hydractive sphere block on my V6 for an allied reason (see my blog) and if this is your problem, it's often best to replace the block wholesale with a good front (less corroded!) hydractive spehere block from a scrapper. The electrovalve itself can be changed but at the rear especially, they're normally well corroded in and difficult to do in-situ. Also the O rings are not easily available and new valves cost over £100 each

vince · Unread post by **vince** » 21 Jun 2009, 09:34

Does it do it any harm running it like that?

Ive got a couple of jobs to do before the National Rally, perhaps we can have a look at this when i come down to yours?

Unread post by **Peter.N.** » 21 Jun 2009, 15:52

Most of my XMs are ticking at less than 10 seconds and have been doing so for many thousands of miles, general wear in the hydraulic department will cause it and unless you are certain of it being caused by one particular component, you could spend a fortune on it - and it wouldn't drive any better.

vince · Unread post by **vince** » 21 Jun 2009, 22:13

Thanks for that Pete,

The problem i have is that it used to tick at 30 seconds and within a day then ticks at 8 seconds. That rules out in my book general wear in the hydraulic department and points to a particular fault, although i do appreciate your comments on the lack of problems running them this way.

Im in no way interested in spending a fortune on this car (it gets its fair share of TLC already) but i do like things to run as they were designed to do so after a chat with Jim earlier today its on the cards for a look in on the National Rally weekend

Mandrake · Unread post by **Mandrake** » 22 Jun 2009, 11:13

Sounds very much like a leaky electrovalve

Inside the valve is a double ended needle valve, which you can see the needle part of here:

http://homepages.igrin.co.nz/simon/imag ... valve4.jpg

and it seems that for whatever reason, the taper on the needle or the seat becomes pitted and it no longer seals completely.

If I had to guess I would say that years of the valve slamming open and shut with particles of grit in the oil eventually leads to surface pitting on the tapers, despite there being a tiny filter gauze on the inlet of the valve.

If only one end of the valve is damaged then it only leaks in one mode - either on or off. When mine went faulty it only leaked in the "on" mode, thus reducing the regulator cycle time down to about 8 seconds as you've noted.

Because the pin will tend to rotate around randomly and the switching action itself may not be entirely positive, you'll possibly find that the leakage rate is different every time it switches from hard to soft mode - it was for me.

Unfortunately replacing the electrovalve is the only remedy to the leakage, but it's unclear how much leakage is required to cause a discernable malfunctioning of the suspension, and how much is just an "annoyance", eg a fast regulator cycle time.

My original valve was causing an 8 second cycle time, when I replaced it with a "good" second hand one it went up well over 30 seconds for over a
year, and then it started getting leaky again, it's now currenly hovering around 12-15 seconds.

Given their high price as a new part and the likelyhood that a second hand one may be just as leaky or as in my case, become leaky after a short time, unless it's materially impacting on the performance of the hydractive system then I would be inclined to ignore it as I have with mine, even though it annoys the perfectionist in me no end

Regards,
Simon

AndersDK · Unread post by **AndersDK** » 22 Jun 2009, 15:12

Hi Simon -

Long time no see ... 8)

I was wondering if it would at all be possible to re-finish the needle and seat in the valve ?
After all its no worse than the earlier type carburetor float needle valves which are known to leak and thus flood the carburetor after years of service.

Unread post by **Peter.N.** » 22 Jun 2009, 16:03

Hi Vince

I to like things to run as they were designed - but it can be an expensive luxury.

Peter

Mandrake · Unread post by **Mandrake** » 23 Jun 2009, 06:57

AndersDK wrote:Hi Simon -

Long time no see ... 8)

I haven't gone yet 8)

I was wondering if it would at all be possible to re-finish the needle and seat in the valve ?
After all its no worse than the earlier type carburetor float needle valves which are known to leak and thus flood the carburetor after years of service.

I suppose it's possible, although I didn't attempt it. The needle is easy to get at, but one of the seats is deep down inside the tubing - on the right on this picture:

http://homepages.igrin.co.nz/simon/imag ... valve2.jpg

The one on the left is only a couple of mm below the edge of the black threaded section.

Getting them apart is the tricky bit, they are held together with locktite and I had to heat mine in the oven to get the locktite to break free without excessive force. People have been known to break them attempting to get them apart.

Regards,
Simon